CN100560216C - Electrostatic cloth bag close-mixing dust collector and its dust removal method - Google Patents

Abstract

The electrostatic cloth bag tightly mixed dust collector and its dust removal method are mainly used for flue gas treatment in power plants and the like. In the dust removal room, a grounded dust collection plate that can be opened and closed is placed between the high-voltage discharge electrode and the cloth bag. The high-voltage discharge electrode and the grounded dust collection plates on both sides form an electrostatic dust removal area, and the cloth bag and the grounded dust collection plates on both sides form a filter. Dust removal area. When the bag is filtered, the grounded dust collection plate is closed. After the flue gas enters the dust removal room, it passes through the electrostatic dust removal area to reach the end of the grounded dust collection plate, and then enters the filter dust removal area; when the bag is blown back to clean dust, the grounded dust collection plate When it is turned on, the gas and dust from back-blowing and dust-cleaning pass directly through the grounded dust-collecting plate to the electrostatic precipitator area, and the dust from back-blowing and dust-cleaning is collected by static electricity. Compared with the existing invention, the dust removal is divided into two stages: when the bag is filtered, the dust concentration of the flue gas entering the bag is greatly reduced by making full use of electrostatic dust removal; remove.

Description

Electrostatic cloth bag close-mixing dust collector and its dust removal method

technical field

The invention relates to a device for removing particles in flue gas or gas, in particular to an electric dust collector and a bag filter, and belongs to the technical field of industrial dust removal.

Background technique

In industrial production, such as combustion devices for power generation and metal smelting, there are often solid dust particles, namely particulate matter, in the exhaust gas. These particles are scattered in the air, forming gray air masses, and drifting with the wind and falling everywhere, polluting the environment. Some particles with very small particle size can enter the human body from the respiratory tract, and a large amount of heavy metals may be enriched on the surface, which will cause great harm to the health of animals, plants and humans. Some links of industrial production also put forward high requirements on the quality of the air, which also puts forward the demand for the removal of particulate matter in the gas.

The dust removal devices used in the prior art include electrostatic precipitators and traditional pulse back-blowing bag dust collectors, etc. In the case of low dust removal efficiency requirements, gravity settling chambers, cyclone separators and water film dust removal can also be used device etc.

Patent WO 02/076618A2 has proposed a kind of advanced electrostatic and the particle collector that cloth bag mixes, and its structure is as shown in accompanying drawing (1). Its main feature is that a discharge electrode is placed between two adjacent rows of filter bags, and a grounding hole plate with a certain opening ratio is placed between this row of electrodes and two adjacent rows of filter bags. A potential difference is applied between the plates to form an electrostatic precipitating area between two orifice plates in the middle of two adjacent rows of filter bags. At the same time, orifice plates are also installed at both ends of the two orifice plates, and the orifice plates are used to seal the end faces on both sides of the filter bag row, so as to prevent the filter bags from being damaged by the high-voltage electric field between the high-voltage discharge electrode and the orifice plate. Its operation mode is as follows: in the normal filter stage of the cloth bag, the flue gas to be filtered enters the advanced mixed particle from the flue gas inlet pipe 11, through the airflow distribution plate 12 in the inlet pipe, the gradually expanding airflow distribution plate 13, and the airflow distribution plate 13 at the dust collector inlet. filter chamber of the collector. The airflow first flows through the airflow barrier plate 23 of the inlet section, and enters the electrostatic precipitating area 24 formed by the high-voltage discharge electrode 21 and the dust collection pole plate 25 with holes grounded, and then the airflow begins to partially pass through the opening on the dust collection pole plate 25 The hole of the hole enters the vicinity of the cloth bag 30, and finally all the gas enters the bag from the outside of the cloth bag 30, and enters the clean gas chamber from the outlet above the bag, and then enters the flue at the tail. When cleaning dust, the pulse gas with relatively high pressure is blown back from the bag, so that the particle layer outside the bag is broken and carried to the electrostatic dust removal area 24 with the air flow, and is charged and partially collected on the grounded hole plate 25 .

The advantage of this invention is that it solves the problem of the previous invention: that is, most of the dust caused by the filter bag row is readsorbed by the adjacent filter bag row or itself. In this invention, when the filter unit is blown back to remove dust, through the action of pulse compressed gas with relatively high energy and volume, the dust and dust can pass through the grounded orifice plate and return to the electrostatic dust collection area between the orifice plate and the electrode It is collected by the orifice plate, which can improve the efficiency of pulse gas blowback to the filter bag, reduce the resistance of the system, and prolong the service life of the filter bag.

In the above-mentioned patent WO 02/076618A2, when the cloth bag is performing normal filtration, the airflow can directly enter the cloth bag area through the holes on the grounding orifice plate, and the existence of these opening areas reduces the effective dust collection area of the grounding plate, thereby reducing the efficiency of electrostatic dust removal. efficiency. For the bag part, if the efficiency of electrostatic precipitator is reduced from 90% to 80%, the dust content in the incoming gas will be doubled, the corresponding cleaning cycle will be shortened, and the service life of the bag will be shortened a lot. . Therefore, improving the efficiency of the electrostatic precipitator before bagging will improve the performance of the entire dust removal system even more.

For the patent WO 02/076618A2, because it adopts the grounded orifice plate as the dust collection pole of the electrostatic precipitator part, and the dust removal efficiency of the electrostatic precipitator has a great relationship with the area of the dust collection pole. Through the calculation of the most commonly used Deutsch model for calculating the dust removal efficiency of the electrostatic precipitator, it is found that the dust collection plate with openings in the patent WO 02/076618A2 has a removal efficiency of less than 60% of the particles in the flue gas, and in fact due to entering the bag filter area The flue gas does not pass through the complete orifice filter area, and the electrostatic precipitator efficiency will be reduced to a certain extent. Without these openings, the dust removal efficiency would reach 90%. For the cloth bag, the dust collecting pole plate after opening the hole increases the particle concentration in the flue gas entering the cloth bag surface from 10% to 40% relative to the concentration of the original flue gas. If the bag is set to clean dust under a specific pressure, the frequency of dust cleaning may be increased to 4 times due to the opening of the dust collector, which accelerates the aging of the bag and consumes more cleaning gas.

Contents of the invention

The purpose of the present invention is to propose a kind of dust collector of electrostatic cloth bag close mixing type and dust removal method thereof, to overcome the weakness of the prior art that does not make full use of electrostatic dust removal under normal filtration conditions, so that the concentration of particles entering the surface of the cloth bag under normal filtration conditions is large The range is reduced, which effectively reduces the system operating pressure drop, the usage of cleaning gas and the wear and aging of the bag, further prolonging the service life of the bag.

Technical scheme of the present invention is as follows:

An electrostatic cloth bag close-mixing dust removal method is characterized in that the method comprises the following steps:

1) The flue gas to be dedusted enters the dust collection room from the inlet of the dust collector, passes through the airflow barrier plate at the inlet section, and passes through the electrostatic dust removal area composed of a high-voltage discharge electrode and a grounded dust collection plate. Structure;

2) The air flow barrier plate at the inlet section is respectively connected with the ends of the grounded dust collection plates on both sides of the bag near the inlet of the dust collector, forming an incompletely closed form of openings at the other ends of the grounded dust collection plates on both sides of the bag;

3) When the cloth bag is normally filtered, the grounded dust collection plate is in the closed state, and the grounded dust collection plate blocks the airflow in the direction of the vertical plate, and the flue gas reaches the tail end of the grounded dust collection plate from the electrostatic dust removal area, and then enters The filter and dust removal area is composed of a cloth bag and grounded dust collecting plates on both sides, and then is filtered and discharged through the cloth bag;

4) When the bag is being cleaned, the grounded dust collection plate is opened to allow the airflow to pass through the plate, so that the dust from the bag cleaning passes through the grounded dust collection plate and returns to the electrostatic precipitator area to capture the dust.

The present invention also proposes an electrostatic cloth bag close-mixing dust collector implementing the operation method, which includes a flue gas inlet pipe, a gradually expanding air flow distribution plate, an air flow distribution plate at the inlet of the dust collector, a dust collection room, and a dust collection room. A high-voltage discharge electrode, an airflow barrier plate at the inlet section, a cloth bag, and a grounded dust-collecting plate arranged between the cloth bag and the adjacent high-voltage discharge electrode, characterized in that: the grounded dust-collecting plate adopts a louver-type dust-collecting pole The airflow blocking plate in the inlet section is respectively connected with the ends of the louvered dust collection plates on both sides of the bag near the entrance, forming an incompletely closed form with openings at the other ends of the louvered dust collection plates on both sides of the bag.

The louver-type dust-collecting plates of the present invention are arranged horizontally.

The present invention also proposes another electrostatic bag close-mixing dust collector implementing the operation method, which includes a flue gas inlet pipe, a gradually expanding air distribution plate, an air distribution plate at the inlet of the dust collector, and a dust collection room, which is arranged in the dust collection room The high-voltage discharge electrode, the airflow barrier plate in the inlet section, the cloth bag and the ground dust collection electrode arranged between the cloth bag and the adjacent high-voltage discharge electrode, it is characterized in that: the ground dust collection electrode adopts double-layer orifice plate structure, the two orifice plates can move relative to each other so that the holes in the two orifice plates are connected or staggered. One end of the bag is connected to form an incompletely closed form of the opening of the other end of the dust collecting plate of the double-layer orifice structure on both sides of the bag.

Compared with the prior art, the present invention has the following advantages and outstanding effects: the method proposed by the present invention ensures the efficiency of the electrostatic precipitator part during bag filtration and the removal of static electricity to the bag dust during bag cleaning, and realizes the whole The improvement of the performance of the dust removal system effectively reduces the operating pressure drop of the system and prolongs the service life of the bag. Existing technologies use orifice plates with fixed holes as electrostatic precipitating plates. During filtering, these holes reduce the dust collecting area on the one hand, and also provide passages for the airflow to directly enter the bag filter area from the electrostatic precipitating area, which becomes a reduction Factors in electrostatic precipitator efficiency. The present invention focuses on the influence of these openings at different stages, adopts a grounded dust collection plate that can be opened and closed to replace the fixed orifice plate design in the prior art, and forms a new electrostatic bag close-mixing dust collector Operation method: During normal filtration, the dust collector plate is closed, blocking the airflow in the direction vertical to the plate, so that the airflow must first pass through the complete electrostatic dust removal part before entering the filter and dust removal near the cloth bag, greatly improving the electrostatic dust removal part. High particle collection efficiency; during the dust cleaning stage, the grounded dust collector plate is opened, allowing the airflow to pass directly through the plate from the vicinity of the bag and return to the electrostatic precipitator area, so as to realize the collection of dust from bag cleaning in the electrostatic precipitator area. This design retains the advantages of the prior art of using static electricity to remove dust and dust from the bag, and at the same time realizes the full use of the electrostatic dust removal area during bag filtration.

After adopting the dust collector and the operation method of the present invention, the area of the dust collection plate when filtering in the electrostatic dust removal area is equivalent to the area of the grounded dust collection hole plate in the existing patent WO 02/076618A2 when no holes are opened, and the flue gas passes through the static electricity. The dust removal efficiency reaches 90% in the dust removal area, which greatly improves the electrostatic dust collection effect. In this way, the airflow filtered by the cloth bag has been filtered by the complete electrostatic precipitator area, and its dust concentration is much lower than that of the gas filtered by the cloth bag in the existing similar technology (in the above calculation, the inlet gas filtered by the improved cloth bag The dust concentration is only 1/4 of the hybrid dust collector of the patent WO 02/076618A2), so the filter pressure drop of the bag will increase slowly, which will also reduce the frequency of back blowing, reduce the energy consumption of the bag, and at the same time reduce the performance and service life of the bag part There will be a big improvement. In addition, when the electrostatic precipitator is vibrating, the grounded dust collection plate is in a closed state, which also avoids the situation in the prior art that the dust may directly pass through the holes of the orifice plate and enter the surface of the bag when vibrating in the electrostatic precipitator area .

Description of drawings

Fig. 1 is the structural schematic diagram of the hybrid particle collector of patent WO 02/076618A2.

Fig. 2 is a three-dimensional structural schematic diagram of an implementation of the electrostatic bag close-mixing dust collector implementing the operating method of the present invention, using horizontal louvers as grounded dust collecting plates that can be opened and closed.

Fig. 3 is a top view of Fig. 2, showing the state and the flow path of the filtered flue gas during normal filtration of the electrostatic bag close-mixed dust collector.

Fig. 4 is a top view of Fig. 2, showing the state of cleaning dust in the bag of the electrostatic bag close-mixing dust collector and the flow path of back-blowing and cleaning gas.

Figure 5a: The front view of the bag and the adjacent grounded dust collection plate in the electrostatic bag close-mixing dust collector realized in Fig. 2 when the bag is filtering.

Figure 5b: In the electrostatic bag close-mixing dust collector realized in Figure 2, the front view of the bag and the adjacent grounded dust collection plate when the bag is blown back and cleaned.

Fig. 6 is a structural schematic diagram of another implementation of the electrostatic bag close-mixing dust collector implementing the operation method of the present invention. Looking down from the top, a double-layer orifice plate that can move relatively is used as the ground dust collection plate. The figure shows the state when the openings of the double-layer orifice plate are staggered to form a barrier to air flow during bag filtration.

Fig. 7 is the state in which the openings of the double-layer orifice plate are connected to each other when the bag is cleaning dust in Fig. 6, so that the airflow and dust generated by the back blowing pass through the orifice plate.

Figure 8a: Double-layer orifice plate grounded dust-collecting pole plate with staggered openings; Figure 8b: Double-layer orifice plate grounded dust-collecting pole plate with openings connected.

In the figure: 1- the gradual expansion section of the dust collector inlet, 2- the side plate of the dust collector, 3- the rear end plate of the dust collector, 5- the ash hopper, 11- the flue gas inlet pipe, 12- the air distribution plate in the inlet pipe, 13- the gradual Expansion airflow distribution plate, 14-airflow distribution plate at dust collector inlet, 21-high voltage discharge electrode, 22-louver type ground dust collection plate, 22a-closed louver type ground dust collection plate, 22b-open louver type ground collection plate Dust plate, 23-airflow barrier plate at the inlet section, 24-electrostatic precipitator area, 25-ground dust collecting orifice plate, 26-double-layer orifice plate grounding dust-collecting plate, 26a-double-layer orifice plate grounding collection with staggered openings Dust pole plate, 26b-opening connected double-layer orifice plate grounding dust collection pole plate, 30-cloth bag.

Detailed ways

Below in conjunction with accompanying drawing, the present invention will be further described:

Fig. 2 is an electrostatic bag close-mixing dust collector for implementing the method proposed by the present invention, which adopts a horizontal louver as a grounded dust collection plate that can be opened and closed. In the figure, the flower board at the outlet of the cloth bag, the clean air chamber above, and the electrode power supply, insulation, vibration, and the dust cleaning auxiliary system of the cloth bag are not drawn. The flue gas enters the dust removal chamber composed of the inlet gradual expansion section 1 of the dust collector, the dust collector side plate 2 and the dust collector rear end plate 3 through the inlet gradual expansion section 1. The air chamber (not shown) is then vented.

Fig. 3 is a plan view from the top of Fig. 2, and the bag of the electrostatic bag close-mixing dust collector is in the working condition of filtering. The flue gas enters the dust collector from the flue gas inlet pipe 11 through the airflow distribution plate 12 in the inlet pipe, the gradually expanding airflow distribution plate 13, and the airflow distribution plate 14 at the inlet of the dust collector. The electrostatic precipitating area 24 formed by the high-voltage discharge electrode 21 and the adjacent louver-type ground dust-collecting electrode plate 22 . A certain potential difference is applied between the high-voltage discharge electrode 21 and the louver-type grounded dust-collecting plate 22 to form an electrostatic precipitating area 24 between the high-voltage discharge electrode 21 and the louver-type grounded dust-collecting plate 22 . At this time, the louvered dust collection plate 22 is closed to form a complete piece. The air flow needs to pass through the electrostatic precipitator area 24 to reach the end of the electrode row composed of the high-voltage discharge electrode 21, that is, to the tail end of the grounded dust collection plate. Under the hindering effect of the rear end plate 3, it turns back into the filter and dust removal area between the cloth bag 30 and the louver type ground dust collection plate 22, as shown by the thicker dotted line in the figure. In this way, the flue gas entering the filter and dust removal area first passes through the electrostatic filtration of a long channel, and its dust concentration will be greatly reduced. In addition, the rapping of the louvered ground dust collecting plate 22 or the high-voltage discharge electrode 21 by the electrostatic precipitator is also selected under the working conditions shown in Figure 3, which can prevent the rapped dust from directly entering the surface of the bag, and also has a negative effect on the filter. The performance has been improved to some extent.

Fig. 4 is the working condition of the electrostatic bag close-mixing dust collector proposed by the present invention when the bag is blown back to clean the dust, and it is also a top view of Fig. 2 from the top down. At this time, the louver-type grounding dust-collecting pole plate 22 is in an open state, that is, each small piece rotates at a certain angle, forming a direct passage from the cloth bag 30 through the slit on the louver-type grounding dust-collecting pole plate 22 and entering the electrostatic precipitating area 24 The channel allows the broken particles on the outer surface of the filter bag caused by back blowing and cleaning to directly enter the electrostatic precipitator area 24 and be charged and collected immediately. Close the louver after the bag cleaning is finished, so that the louver-type grounding dust collection pole plate 22 still forms a complete piece, and restores the normal filtering state in Fig. 3 .

Fig. 5 is a schematic diagram of the filter bag and the adjacent plate electrode in the state of filtering and cleaning, wherein Fig. 5a is the state of bag filtering, and Fig. 5b is the state of bag cleaning. When filtering, the louver-type plate is closed 22a to form a complete piece. When the bag 30 is cleaned, the louver is opened 22b to pass directly through the slit from the bag to the passage of the electrostatic dust removal area, and particle debris can pass through these passages and enter the electrostatic dust removal area. And was captured.

Fig. 6 is a structural schematic diagram of another embodiment of the electrostatic bag close-mixing dust collector provided by the present invention, which adopts a double-layer orifice plate grounded dust collection plate 26 that can be staggered. This figure shows the double-layer hole when the bag is normally filtered The plate is grounded and the dust collection plate is closed, that is, the state when the openings of the two orifice plates are staggered and arranged to block the airflow. The flue gas enters the dust removal chamber from the flue gas inlet pipe 11 through the airflow distribution plate 12 in the inlet pipe, the gradually expanding airflow distribution plate 13, and the inlet airflow distribution plate 13 of the dust collector. The electrostatic precipitating area 24 is formed by the high-voltage discharge electrode 21 and the adjacent double-layer orifice-plate grounded dust-collecting electrode plate 26 . A certain potential difference is applied between the high-voltage discharge electrode 21 and the double-layer orifice-plate grounded dust-collecting electrode plate 26 to form an electrostatic precipitating area 24 . When the cloth bag 30 is filtering, the double-layer orifice plate is grounded and the dust collection plate 26 is closed, that is, the openings of the two orifice plates are staggered, so that the filtered smoke passes through the electrostatic dust removal area 24 and reaches the end of the electrode row composed of the high-voltage discharge electrode 21. Under the hindrance of the rear end plate 3, it turns back into the circulation area between the cloth bag 30 and the adjustable double-layer orifice plate grounding dust collection plate 26, as shown by the thicker dotted line in the figure. In this way, the flue gas entering the filter and dust removal area has been electrostatically filtered through a long channel, and its dust concentration will be greatly reduced. In addition, the rapping of the double-layer orifice grounded dust collection plate 26 or the high-voltage discharge electrode 21 in the electrostatic precipitator is also selected under the working conditions in Figure 6, so that the rapped dust can be prevented from directly entering the surface of the bag, and the There is a certain improvement in the filtration performance.

Figure 7 shows the state in which the double-layer orifice plate grounding dust collection plate 26 is opened when the bag is being cleaned in Figure 6, that is, the openings of the two orifice plates are aligned and arranged to allow the airflow and dust generated by the back-blowing to pass through the orifice plate. At this time, the double-layer orifice grounding dust-collecting pole plate 26 is opened, that is, the openings of the two orifice plates are arranged in alignment, forming that the cloth bag 30 directly passes through the opening of the double-layer orifice grounding dust-collecting pole plate 26 and enters the electrostatic precipitator. The channel in area 24 allows the broken particles on the outer surface of the filter bag caused by back-blowing and cleaning to directly enter the electrostatic precipitator area 24 and be charged and collected immediately, and then close the dust-collecting electrode plate 26 that can be grounded with a double-layer orifice plate. That is, the openings of the two orifice plates are arranged in a staggered manner, and the normal filtering state in Fig. 6 is restored.

FIG. 8 is a specific structure of a realization of the double-layer orifice plate in the implementation form shown in FIG. 6 and FIG. 7 , as a schematic diagram of closing and opening of the double-layer orifice plate. When the cloth bag is filtered, the double-layer orifice plate is grounded and the dust-collecting pole plate is closed, forming a double-layer orifice-plate grounded dust-collecting pole plate 26a with openings staggered, and the airflow cannot pass through it vertically; The plates are opened to form a double-layer orifice grounding dust-collecting pole plate 26b with openings connected to each other, and the airflow can pass through the openings vertically through the double-layer orifice grounding dust-collecting pole plate.

Claims (4)

1. a static electric cloth bag compact mixed type dust collection method is characterized in that this method comprises the steps:

1) treat that the dedusting flue gas enters dust chamber by the deduster inlet, through entrance air-flow baffler, enter the electrostatic precipitation zone that is made of high voltage discharge electrode and ground connection dust collecting pole plate, described ground connection dust collecting pole plate adopts the structure that can open and close;

2) entrance air-flow baffler links to each other near the end that deduster enters the mouth with the ground connection dust collecting pole plate of cloth bag both sides respectively, forms the incomplete closing form of the ground connection dust collecting pole plate other end opening of cloth bag both sides;

3) when the cloth bag normal filtration, the ground connection dust collecting pole plate is in closed condition, the ground connection dust collecting pole plate intercepts the air-flow of vertical plate direction, flue gas is arrived the tail end of ground connection dust collecting pole plate by the electrostatic precipitation zone, enter the dust removal by filtration zone that the ground connection dust collecting pole plate by cloth bag and both sides constitutes then, discharge through the cloth bag filtration again;

4) when cloth bag carries out deashing, the ground connection dust collecting pole plate is opened, and allows air-flow to pass pole plate, and the airborne dust when making the cloth bag deashing passes the ground connection dust collecting pole plate and gets back to the electrostatic precipitation zone, realizes the capture to airborne dust.

2. implement the static electric cloth bag compact mixed type dust remover of method according to claim 1 for one kind, contain the smoke inlet pipeline, dust chamber, be arranged on the high voltage discharge electrode in the dust chamber, entrance air-flow baffler, cloth bag and be arranged in described cloth bag and adjacent high voltage discharge electrode between the ground connection dust collecting pole plate, it is characterized in that: described ground connection dust collecting pole plate adopts venetian blind type dust collecting pole plate (22), described entrance air-flow baffler links to each other near an end that enters the mouth with the venetian blind type dust collecting pole plate of cloth bag both sides respectively, forms the incomplete closing form of the venetian blind type dust collecting pole plate other end opening of cloth bag both sides.

3. according to the described static electric cloth bag compact mixed type dust remover of claim 2, it is characterized in that: described venetian blind type dust collecting pole plate adopts lateral arrangement.

4. implement the static electric cloth bag compact mixed type dust remover of method according to claim 1 for one kind, contain the smoke inlet pipeline, dust chamber, be arranged on the high voltage discharge electrode in the dust chamber, entrance air-flow baffler, cloth bag and be arranged in described cloth bag and adjacent high voltage discharge electrode between the ground connection dust collecting pole plate, it is characterized in that: described ground connection dust collecting pole plate adopts double-deck AND DEWATERING FOR ORIFICE STRUCTURE, two orifice plates can relatively move, two holes in the orifice plate are in to be communicated with or the state that staggers, described entrance air-flow baffler links to each other the incomplete closing form of the dust collecting pole plate other end opening of the double-deck AND DEWATERING FOR ORIFICE STRUCTURE of formation cloth bag both sides with the dust collecting pole plate of the double-deck AND DEWATERING FOR ORIFICE STRUCTURE of cloth bag both sides near an end of inlet respectively.

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